1. Field of the Invention
The present invention pertains to a light-emitting diode comprising LED chips, that is, light-emitting diode chips.
2. Description of the Prior Art
Examples of this type of light-emitting diode are disclosed in Japanese Kokai Patent No. Hei 11(1999)-346,007 and Japanese Patent No. 2,982,553. The light-emitting diode disclosed in the former has LED chips and a pair of electrostatic protective elements in the concave part (or cup) made in one lead of a pair of leads. One electrode of a pair of electrodes of the LED chips is electrically connected to the lead holding the LED chip through the electrostatic protective elements, and the other electrode is connected to the electrostatic protective element and also electrically connected to another lead by wire bonding technique.
On the other hand, according to the latter document, a single LED chip is electrically connected such that the chip bridges a pair of leads. This type of mounting method is called flip-chip mounting. The advantage of flip-chip mounting is that it can prevent opening of wires for connection in temperature cycles, which can occur in the structure shown in the former document.
The structure of flip-chip mounting disclosed in the above documents shows resin, which can conventionally seal the diode chips from outside. In this case, because of relatively large thermal expansion coefficient of the resin, stress is generated in the LED chip when force is applied to the pair of leads from the resin due to thermal expansion and contraction, and the chip may be destroyed in the worst scenario. Consequently, the object of the present invention is to present a light-emitting diode with which the LED chip will not be destroyed.
The present invention provides a light-emitting diode, having an LED chip electrically connected to a pair of leads characterized in that said LED chip is mounted on a plate-shaped wiring means and connected to said pair of leads by said wiring means.
Preferably, said flexible wiring means is a single means.
Preferably, at least one of said pair of leads includes a support part for supporting a portion of said wiring means on which said LED chip is mounted.
Preferably, said support part is concave such that said support part can surround said LED chip.
Preferably, said wiring means comprises a 3-dimensional wiring means.
Preferably, said wiring means comprises a circuit board or tape-like electrical wire.
Preferably, an electronic element is further mounted on said wiring means, said element being selected from a group of a protective element and a sensor to monitor heat or light.
Preferably, said wiring means includes a pair of chip mounting electrodes mutually separated by only a relatively short distance and a pair of lead connecting electrodes mutually separated by a relatively long distance.
Preferably, said wiring means has flexibility.
Furthermore, the present invention provides a method of producing a light-emitting diode, comprising the steps of mounting at least one LED chip having a pair of electrodes on a plate-shaped wiring means with at least a pair of electrical paths, and mounting said wiring means on a pair of leads and thereby electrically connecting said pair of electrodes to said pair of leads by said pair of electrical paths.
Preferably, said step of mounting at least one LED chip comprises a step of mounting several LED chips on a single substrate, where said substrate includes s plurality of wiring means.
Preferably, said method further comprises a step of cutting said substrate to have specific dimensions such that said plurality of wiring means are separated after said step of mounting several LED chips.
Preferably, said method further comprises a step of testing said LED chips using said wiring means after said step of separating said plurality of wiring means.
According to the light-emitting diode of the present invention, the LED chip is mounted on a plate-shaped wiring means. The wiring means comprises a pair of conductive paths electrically connecting between a pair of opposing surfaces. One of the surfaces is for mounting an LED chip. The pair of conductive paths is electrically connected to the LED chip and extends from the LED-mounting section to the lead-connecting sections. The lead-connecting sections are connected to the corresponding lead by soldering. At least one of the lead-connecting sections overlap the LED chip mounted on the wiring means, and as a result, the LED is stabilized by being supported by the lead. It is preferred that the plate-shaped wiring means have at least some flexibility, but it can also be rigid.
Moreover, according to the method of producing semiconductor elements of the present invention, the LED chip is firstly mounted on a substrate including a single wiring means or a set of plurality of wiring means. In the latter case, the substrate is later cut into the appropriate dimensions and the plurality of wiring means can be separated. Then the required tests are performed on the LED chip mounted on the wiring means. When the tests have been completed, the wiring means is connected to the corresponding lead by a conventional method such as soldering, etc.